Sjogren-Larsson syndrome (SLS) is an inherited neurocutaneous disorder caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase (FALDH). The symptoms of SLS include ichthyosis, mental retardation and spasticity, and are hypothesized to arise from the deranged metabolism of fatty aldehydes and precursor lipids such as fatty alcohols, which cannot be metabolized by FALDH. However, little is known about the underlying biochemical pathogenesis of SLS and effective therapy for the disease is lacking. The long-term goal of our research is to understand the pathogenic mechanisms causing the symptoms of SLS in order to develop specific therapy for affected patients. To gain insight into the biochemical and pathologic abnormalities in SLS, we will extensively characterize the biochemical and phenotypic features of a new FALDH-deficient gene knockout mouse model for SLS, and examine the role of genetic background on its phenotypic expression. Cultured keratinocytes, oligodendrocytes and mixed neuronal cells from FALDH-deficient mice will be investigated to reveal cell- specific lipid abnormalities. Using FALDH-deficient mice and cultured cells from SLS patients, we will determine whether FALDH is implicated in the metabolism of fatty aldehydes and fatty alcohols generated from farnesol, w-hydroxy fatty acids and (R)-trioxilin A3. These pathways are potentially amenable to therapeutic intervention with dietary modification and pharmacologic agents. Using immunologic and chemical methods together with mass spectrometry, we will identify the proteins that are covalently modified by fatty aldehyde in SLS cells to gain insight into the pathogenic mechanisms responsible for the cutaneous and neurologic symptoms. In summary, these studies will define the aberrant metabolism in SLS cells arising from FALDH deficiency and take advantage of the first animal model for SLS to uncover new pathogenic mechanisms responsible for cutaneous and neurologic symptoms. This research is directed at investigating Sjogren-Larsson syndrome (SLS), an inherited metabolic disease affecting the skin and brain of children and adults. We will study the abnormal fat metabolism that occurs in skin cells from patients to discover the cause of the symptoms, and characterize a newly developed mouse that has the same metabolic problem as people with SLS in hopes of developing an effective treatment.